Hyundai Santa Fe Motor 2.0 Turbo Intercooler D4ea

Good afternoon, I have a problem with a vehicle Hyundai Santa Fe 2.0 D4a Motor, I took the mécanic for review/change of the dentada strap and when checking around it found oil in the cooling circuit (radiator and reservoir). He told me that it can be the oil cooler or the joint. Did anyone have a similar problem? How did he solve it? Already very grateful for the comments

The oil cooler is usually punctured and filtered oil into the cooling system, it would have to be disassembled and tested.